1. Field of the Invention
The present invention generally relates to a battery assembly for providing power to an integrated circuit or a semiconductor chip, often used in a remote control device for a television, VCR, audio system and the like. More specifically, the instant invention relates to a battery assembly which enables an integrated circuit to be properly powered down upon removal of the battery.
2. Description of Related Art
In a battery powered device, such as a remote control unit used for a television, VCR, audio system or the like, a problem known as IC latch-up occurs when the operating voltage of the remote control unit falls below the minimum operating voltage of the IC (Integrated Circuit).
In the past, the problem of IC latch-up has been solved with the utilization of a low voltage detector circuit. FIG. 1 illustrates an example of how a low voltage detector circuit is employed with a battery powered IC. The circuit 40, in FIG. 1, simply illustrates the power section of a complete circuit used with an IC in a remote control unit. In the circuit 40 of FIG. 1, a battery 46 has positive and negative sides. The negative side is connected to ground 48. The positive side of battery 46 is connected to the Vdd port of IC 42 through line 50. IC 42 is also connected to ground at 52. A low voltage detector circuit 44 receives positive voltage from line 54 and is grounded at 56. Line 58 goes from low voltage detector circuit 44 to the RESET port of IC 42. Furthermore, a resistor 60 is connected between lines 50 and 58, while capacitor 62 is connected between line 58 and ground 64. In circuit 40, illustrated in FIG. 1, the operation of IC 42 is stopped by providing an output from the low voltage detector circuit 44. When low voltage detector circuit 44 detects a reduction of voltage, the voltage detector circuit outputs a LOW signal on line 58 just before the minimum operating voltage of the IC 42 is reached. This low level signal on line 58 is input to the RESET port of IC 42. This causes the IC to properly stop operation, that is, to properly power down. If, at this time, the batteries are replaced, and the voltage level is thereafter restored to a level higher than the minimum operating voltage of the IC, it will return to its normal operation.
FIG. 1 illustrates the circuit of a microcomputer or integrated circuit used in a remote control device. Specifically, if the power supply voltage to the microcomputer or integrated circuit falls below the specified level, certain undesired operations may be performed or the contents of a memory register may be lost. When power supply voltage returns to normal (when batteries are replaced) it may be necessary to initialize the microcomputer or integrated circuit before normal operations can be performed. Thus, the low voltage detector circuit is employed to protect a microcomputer, or integrated circuit, from this type of problem.
If a low voltage detector circuit is not used in the circuit 40, there is an advantage to use the IC to its absolute operating limit in order to prolong the life of the batteries. However, in this case, even after the IC stops operating, the RESET port will not have gone low yet. In this condition, even if the batteries are replaced, since the IC has not been reset, the IC will not operate properly, as a result. This is the IC latch-up condition. In order to prevent this type of latch-up condition, it is necessary to reset the IC before the new batteries are installed. In order to accomplish this, enough time must be allowed for the circuit to discharge itself until the RESET port goes low, or to incorporate some methods to discharge the circuit automatically. The employment of a low voltage detector circuit, as described above, provides for additional expense, in parts, as well as labor, in manufacturing a remote control unit as described above. This and other disadvantages described above are overcome through the use of the present invention, which provides a low cost alternative to the use of a low voltage detector circuit in a remote control unit.